Saddles for flexible thin printing plates



United States Patent [72] Inventors Roy W. Prince Lexington,Massachusetts; Manuel C. Uy, Glen Burnie, Maryland [21] Appl. No.713,956 [22] Filed March 18, 1968 [45] Patented Nov. 3, 1970 [73]Assignee W. R. Grace & Co.

New York, New York a corporation of Connecticut [54] SADDLES FORFLEXIBLE THIN PRINTING PLATES 6 Claims, 5 Drawing Figs.

[52] 11.8. C1 101/378, 101/415.1 [51] Int. Cl B41t27/06 [50] Fieldol'Search 101/378, 382, 387, 415.1

[56] References Cited UNITED STATES PATENTS 2,771,031 11/1956 Knapp101/415.1 2,966,848 1/1961 Faeber 101/378X 2,970,540 2/1961 Wirthl01/4l5.l f

3,045,595 7/1962 Guriw 101/415.1 3,083,737 4/1963 Mestral 26/9X3,136,026 6/1964 Mestral 26/2X 3,154,837 11/1964 Mestral 26/2X 3,237,5583/1966 Fagg 101/378X 3,353,481 11/1967 Antonucci 101/382X 3,376,8144/1968 schollenberger, 101/378UX 3,384,014 5/1968 Berg 101/415.l3,127,834 4/1964 Tyma et a1. 101/4l5.l

Primary Examiner Robert E. Pulfrey Assistant Examiner- Eugene H.Eickholt Att0rney- Richard P. Plunkett and Kenneth E. Prince PatentedNov. 3, 1970 Sheet 1 012 INVENTORS R0 y W. Prince Manuel 0. Uy

BY fi ATTORNEY Patented Nov. 3, 1970 Sheet of 2 v I NVENTO S Roy W.Prince Manuel 6 Uy SADDLES FOR FLEXIBLE THIN PRINTING PLATES In theprinting field today, especially in the newspaper business, a largenumber of rotary printing presses having cylinders originally designedfor stereotypes, are widely employed. With the advent ofphotocomposition, flexible, thin plates from photopolymerized orphotocured polymeric systems and metal photoengravings are now beingemployed. However, with polymeric and photoengraved plates, it is notnecessary to form plates of the same thickness as previously formedmetal stereotypes. Obviously since existing presses are made for metalstereotype plates of preset, relatively thick dimensions, the adaptionof the presses for thin flexible plates generates several problems. Forexample, it is necessary that the new system for the thin plates beformed so as to have substantially the same thickness as the normalmetalstereotype plate in order to use existing presses and cylinders.Additionally, the plate must be easily adjusted to register true on thepress. Furthermore, it is necessary that the plate be clampable byconventional existing means and be readily removable from the cylinderin the shortest possible time.

It is obvious that if a printing cylinder which is adapted for receptionof stereotype plates, is to be mounted with a thin flexible printingplate instead of the normal stereotype, a backing plate or saddle ofsufficient thickness in combination with the thin flexible printingplate to essentially correspond to the thickness of the stereotype mustbe employed. M oreover, said backing or saddle should be of sufficientrigidity to withstand the pressure applied when the saddle with plateattached thereto is clamped on the printing cylinder.

One method of attachingthe thin flexible printing plate to the saddlethat has been suggested by the prior art is adhesion caused by gluingthe printing plate on to the saddle, after which the saddle is mountedon the printing cylinder in the same manner as the stereotype plate.This method, however, has the drawback that the rigidity of the adhesivebond prevents subsequent registering and adjustment. Additionally, afteruse the removal of the plate from the saddle can cause damage to thesaddle and/or the plate thereby curtailing its useful life. Anotherdrawback to this system is the extended clean up time necessary toremove the adhesive from the saddle. Another method of adhering printingplates to printing cylinders is the use of magnetic force or vacuum.However, such systems contemplate printing cylinders of intricate designand of sufficient diameter to make up the difference between thethickness of the stereotype and the thin flexible printing plate.Additionally, such systems preclude the use of stereotypes on theprinting press and thus precludes flexibility in the system.

Still another method of affixing thin printing plates to printingcylinders adapted for stereotypes is the use of a support adapted toengage thin printing plates by means of hooks which extend through saidprinting plate into the printing area. Such a system has the drawbackthat said hooking elements could engage and damage the materialreceiving the print from the printing plate.

One object of the instant invention is to provide an arrangement formounting thin flexible printing plates on printing cylinders of rotaryprinting presses normally designed for stereotypes. Another object ofthe instant invention is to provide an arrangement whereby rotaryprinting presses having printing cylinders designed for stereotypes canconvert readily to the employment of thin flexible printing plates.Still another object of the instant invention is to provide a saddle formounting thin flexible printing plates which permits adjustment andregister thereof. Yet another object of the instant invention is toprovide a saddle for mounting thin flexible printing plates which deviceaffords ready removal of the printing plate therefrom. I

These and other objects of the invention are accomplished by providingthin printing plates with either or both out out portions for theengagement of locking means, e.g. fingers, pins or hooks or adhesivebonding means at their two transverse edge regions. The cut out portionsor adhesive bonding means or both are then engaged in the recessedportion traverse the width of the underside near each end of a saddlewith hooks, pins, locking means or adhesive bonding material to maintainthe printing plate in register with said saddle. The use of theunderside ofthe saddle to register and affix a thin flexible printingplate thereto insures fullest employment of the printing face of thesaddle and assurance that the material to be printed on won't be torn bylocking arrangements projecting from the printing face of the saddle.

The various and sundry novel features of this invention are pointed outin the claims annexed to and forming a part of this specification. Theinvention will now be more fully explained with reference to the annexeddrawings which constitute a part of this application. Although thesaddle system described herein is operable for both rotary printingcylinders and flat bed presses, for purposes of explanation thespecification description which follows will refer to arcuate saddlesfor rotary printing cylinders.

Reference is now made to the drawings wherein similar reference numbersrefer to similar parts throughout the various views:

FIG. 1 is a cross-sectional view of the saddle and flexible printingplate in an assembled relationship mounted on a printing cylinder;

'FIG. 2 is a perspective view of the underside of the saddle showingthe-recessed portion, the bar attachable therein and the flexibleprinting plate;

FIG. 3 is an exploded cross-sectional view of one method of attachingthe printing plate to the saddle mounted on a printing cylinder;

FIG. 4 is an exploded cross-sectional view of another means of attachingthe printing plate to the saddle which is mounted on the printingcylinder; and

FIG. 5 is still another exploded cross-sectional view of another methodof attaching the printing plate to the saddle which is mounted 'on aprinting cylinder.

With reference to the drawings, a flexible printing plate 10 with araised image or relief printing portion ll is mounted on a saddle 12 asshown in FIG. 1. The saddle 12 consists of a rigid'material of uniformthickness and of generally arcuate shape. The saddle is mounted on aprinting cylinder I3 equipped with either fingers for tension lockup byexten sion into tapered grooves 15 in the-saddle or conventionalcompression lockup by contacting rings around the circumference of thecylinder with the bevelled edges of the saddle 30. The thin printingplate 10 is provided at its respective op-. posite straight traverseedge portions with a number of spaced cutouts 1 6, which cutouts acceptand have projected therethrough register pins 17 mounted in the recesses21 traversing the width of the underside near each end of the saddle l2.Additionally,-depending on the type of bonding of the printing plate tothe saddle, the printing plate may have interspaced between the cutoutsfor the register pins, openings 18 for the projection therethrough offastening means 19 to secure a register bar 20 into the recess 21situated transverse the width of the underside near each opposite end ofthesaddie 12 thereby tensioning the flexible printing plate 10 aroun thecurvature of the saddle l2.

In referring to FIGS. 3-5, it should be noted that the foot or endportion 22 of saddle I2 is of such thickness as to allow the inclusionof the thickness of the backing material for the printing plate to passthere between it and the printing cylinder 13.

Various means can be used to hold the ends 23 of printing plate 10 inthe recess position 21 of saddle 12. One method as previously describedsupra and as shown in the views in FIGS;

elements 24, 25 are shown in FIG. 4. Said elements can beformed ofsynthetic materials such as nylon or similar material and after thermaltreatment one element is maintained in the form of loops 24 and isadhered to the back portion 28 of recess 21 of the saddle 12 whereas theother element in the form of hooks 25 is adhered to the ends 23 of theprinting plate. Elements 24 and 25 are contacted to form a separablefastening device. Such elements are known from U.S. Pat. Nos. 2,717,437;3,009,235; 3,083,737; 3,114,952; 3,136,026 and 3,154,837 all assigned toVelcro Company. If desired, elements 24 and 25 can have aperturestherein for the passage of register pins 17 mounted in the back portion28 of recess 21 in saddle 12. Still another method of holding theprinting plate on and in register with the saddle is shown in FIG. 5.Therein a plastic material 26, e.g. polyethylene having male buttonlikeprongs 27 extending therefrom is adhered to the back portion 28 ofrecess 21 and similar plastic material 26 having female openings 29registerable with said buttonlike prongs 27 is adhered to the ends 23 ofthe flexible printing plate 10 in a manner such that the openings 29extend therefrom. By means of snapping said male buttonlike prongs 27into said female openings 29, the printing plate is adhered to and inregister with saddle 12.

The flexible base of the printing plate is preferably composed ofplastic e.g. Mylar" but can also, if desired, be composed of rubber,aluminum or other metal foil. The printing or relief surface of theprinting plate 11 is preferably composed ofa polymeric or plasticmaterial, e.g. a synthetic organic resin or polymer but can also becomposed of rubber, molded plastic, metal, etc. For example, in itspreferred form it may be composed of a photocured polymer made after themanner described in U.S. Pat. application Ser. No. 674,773 filed October12, 1967 and assigned to the same assignee. Additionally, it can becomposed of a photopolymerized addition polymer as described in U.S.Pat. Nos. 2,760,863; 2,791,504; 2,927,002; 3,024,180 and 2,923,673.

The assembled flexible printing plate and saddle are fastened on to theprinting cylinder or flat bed by conventional means. For example atension lockup consisting of fingers extending from the circumference ofthe printing cylinder into slots on the inner arcuate surface of thesaddle at each end can be employed. Additionally, the saddle can also beused on rotary presses equipped with rings for compression lockup.

' The saddles operable in the instant invention are of rectangular shapeand they can be of either flat bed or arcuate configuration. The saddleshould be of sufficient thickness and rigidity that it is stiff and doesnot flex appreciably on mounting. A saddle thickness of aboutthree-sixteenths to about three-eighths inches is operable for flexibleplates ranging in thickness from 10 to 80 mils.

The recess portion of the underside of the saddle across the widththereof is located approximately one-eighth to onefourth inch from eachopposite end of the saddle and has a width of approximately one-fourthto one-half inch and a depth of approximately one-eighth inch. Thesedimensions are for a printing plate having a printing surface ofapproximately 22 inches in length. For larger or smaller printing areasthe dimensions of the recess can be varied as the need arises.

The saddle can be made from various materials. Operable materialsinclude, but are not limited to, metals, e.g. magnesium, aluminum,steel, etc., hard semi rigid plastics, e.g. phenol formaldehyde,acrylic, phenolic, nylon and the like light weight materials and fiberglass-impregnated cellulosic materials.

Advantages of the instant invention include the mounting of flexibleprinting plates on printing cylinders using conventional printingcylinders and lockups. The saddle is reuseable and the polymericprinting plate can be readily removed therefrom to be reused at a laterdate, thereby allowing the printer to maintain a minimum inventory ofsaddles and assuring the reuse of the flexible printing plate in thefuture.

We claim:

1. An arrangement for mounting on a printing cylinder which comprises incombination, a curved stiff rectan ular backing plate of one-piececonstruction having general y U- shaped recess portions transverse itswidth on its underside near to but spaced from each opposite end, saidends having a rounded configuration, a flexible printing plate disposedover said backing plate and of a length sufficient to extend around theopposite rounded ends of said backing plate and across the recessportions, the thickness of said backing plate between said recesses andsaid opposite ends being less than the thickness of said backing platebetween said recesses by an amount substantially equal to the thicknessof said printing plate, and two separable securing bars associated withregister pins for engagement with openings in the printing plate, saidseparable securing bars securing the printing plate to the backing platewithin the generally U-shaped recess portions by a fastening means.

2. The arrangement of claim 1 wherein tapered grooves are providedintermediate the recess portions for tension lockup on a printingcylinder.

3. The arrangement of claim 1 wherein the register pins are securedwithin the recess portions and projected through the printing plate andthrough register apertures disposed in said securing bars.

4. The arrangement of claim 3 wherein screws secure the securing barswithin the recesses to the backing plate.

5. The arrangement of claim 1 wherein the separable bars are each formedof two elements having engaging hooks and loops. I

6. The arrangement of claim 1 wherein male buttonlike prongs extend fromthe separable bars within the recesses for receiving openings of theprinting plate.

